The N-Terminal Domain of ERK1 Accounts for the Functional Differences with ERK2

The Extracellular Regulated Kinase 1 and 2 transduce a variety of extracellular stimuli regulating processes as diverse as proliferation, differentiation and synaptic plasticity. Once activated in the cytoplasm, ERK1 and ERK2 translocate into the nucleus and interact with nuclear substrates to induce specific programs of gene expression. ERK1/2 share 85% of aminoacid identity and all known functional domains and thence they have been considered functionally equivalent until recent studies found that the ablation of either ERK1 or ERK2 causes dramatically different phenotypes. To search a molecular justification of this dichotomy we investigated whether the different functions of ERK1 and 2 might depend on the properties of their cytoplasmic-nuclear trafficking. Since in the nucleus ERK1/2 is predominantly inactivated, the maintenance of a constant level of nuclear activity requires continuous shuttling of activated protein from the cytoplasm. For this reason, different nuclear-cytoplasmic trafficking of ERK1 and 2 would cause a differential signalling capability. We have characterised the trafficking of fluorescently tagged ERK1 and ERK2 by means of time-lapse imaging in living cells. Surprisingly, we found that ERK1 shuttles between the nucleus and cytoplasm at a much slower rate than ERK2. This difference is caused by a domain of ERK1 located at its N-terminus since the progressive deletion of these residues converted the shuttling features of ERK1 into those of ERK2. Conversely, the fusion of this ERK1 sequence at the N-terminus of ERK2 slowed down its shuttling to a similar value found for ERK1. Finally, computational, biochemical and cellular studies indicated that the reduced nuclear shuttling of ERK1 causes a strong reduction of its nuclear phosphorylation compared to ERK2, leading to a reduced capability of ERK1 to carry proliferative signals to the nucleus. This mechanism significantly contributes to the differential ability of ERK1 and 2 to generate an overall signalling output

Nuclear Entry of Activated MAPK Is Restricted in Primary Ovarian and Mammary Epithelial Cells

The MAPK/ERK1/2 serine kinases are primary mediators of the Ras mitogenic signaling pathway. Phosphorylation by MEK activates MAPK/ERK in the cytoplasm, and phospho-ERK is thought to enter the nucleus readily to modulate transcription.Here, however, we observe that in primary cultures of breast and ovarian epithelial cells, phosphorylation and activation of ERK1/2 are disassociated from nuclear translocalization and transcription of downstream targets, such as c-Fos, suggesting that nuclear translocation is limited in primary cells. Accordingly, in import assays in vitro, primary cells showed a lower import activity for ERK1/2 than cancer cells, in which activated MAPK readily translocated into the nucleus and activated c-Fos expression. Primary cells express lower levels of nuclear pore complex proteins and the nuclear transport factors, importin B1 and importin 7, which may explain the limiting ERK1/2 import found in primary cells. Additionally, reduction in expression of nucleoporin 153 by siRNA targeting reduced ERK1/2 nuclear activity in cancer cells.ERK1/2 activation is dissociated from nuclear entry, which is a rate limiting step in primary cells and in vivo, and the restriction of nuclear entry is disrupted in transformed cells by the increased expression of nuclear pores and/or nuclear transport factors

Thermal Transport in Micro- and Nanoscale Systems

Small-scale (micro-/nanoscale) heat transfer has broad and exciting range of applications. Heat transfer at small scale quite naturally is influenced – sometimes dramatically – with high surface area-to-volume ratios. This in effect means that heat transfer in small-scale devices and systems is influenced by surface treatment and surface morphology. Importantly, interfacial dynamic effects are at least non-negligible, and there is a strong potential to engineer the performance of such devices using the progress in micro- and nanomanufacturing technologies. With this motivation, the emphasis here is on heat conduction and convection. The chapter starts with a broad introduction to Boltzmann transport equation which captures the physics of small-scale heat transport, while also outlining the differences between small-scale transport and classical macroscale heat transport. Among applications, examples are thermoelectric and thermal interface materials where micro- and nanofabrication have led to impressive figure of merits and thermal management performance. Basic of phonon transport and its manipulation through nanostructuring materials are discussed in detail. Small-scale single-phase convection and the crucial role it has played in developing the thermal management solutions for the next generation of electronics and energy-harvesting devices are discussed as the next topic. Features of microcooling platforms and physics of optimized thermal transport using microchannel manifold heat sinks are discussed in detail along with a discussion of how such systems also facilitate use of low-grade, waste heat from data centers and photovoltaic modules. Phase change process and their control using surface micro-/nanostructure are discussed next. Among the feature considered, the first are microscale heat pipes where capillary effects play an important role. Next the role of nanostructures in controlling nucleation and mobility of the discrete phase in two-phase processes, such as boiling, condensation, and icing is explained in great detail. Special emphasis is placed on the limitations of current surface and device manufacture technologies while also outlining the potential ways to overcome them. Lastly, the chapter is concluded with a summary and perspective on future trends and, more importantly, the opportunities for new research and applications in this exciting field

Gustilo type IIIC open tibia fractures with vascular repair: minimum 2-year follow-up

PMID = 2727301

Pulmonary artery banding and venous bidirectional cava-pulmonary shunt for two-stage arterial switch procedure in late referral of patients with transposition of the great arteries and intact ventricular septum: Midterm results

PubMed ID: 31230611Objective: Two-stage arterial switch operation and left ventricle retraining are necessary for the patients with left ventricle dysfunction and transposition of great vessels with intact ventricular septum (TGA-IVS) who are referred late.Material and methods: Forty-seven patients with the diagnosis of TGA-IVS and left ventricle dysfunction who underwent arterial switch operation in our centre between July 2013 and August 2017 were analysed retrospectively. The inclusion criteria for left ventricle retraining were patients older than 2 months of age at presentation, having an echocardiographic left ventricle mass index of less than 35 g/m, and having an echocardiographic banana-shaped left ventricle geometric appearance. The patients were divided into two groups: pulmonary artery banding and Blalock Taussig shunt were performed as the initial surgical procedure for later arterial switch operation in Group I (n = 19) and pulmonary artery banding and bidirectional cava-pulmonary shunt in Group 2 (n = 28).Results: The average age was found to be 122.3 ± 45.6 days in Group I and 145.9 ± 37.2 days in Group II. There was no statistically significant difference (p = 0.232 versus p = 0.373) between the average left ventricle mass index of the two groups neither before the first stage nor the second stage (26.6 ± 4.8 g/m versus 25.0 ± 4.9 g/m and 70.5 ± 12 g/m versus 673.8 ± 12.0 g/m, respectively). The average time interval for the left ventricle to retrain was 97.7 ± 42.9 days for Group I and 117.3 ± 40.3 days for Group II, significantly lower in Group I (p = 0.027). The time spent in ICU, length of the period during which inotropic support was required, and the duration of hospital stay were significantly higher in Group I (p<0.001, p < 0.001, and p < 0.00, respectively).Conclusion: Pulmonary artery banding and bidirectional cava-pulmonary shunt can be performed as a safe and effective alternative to pulmonary artery banding and arterial Blalock Taussig shunt for patients with TGA-IVS in whom arterial switch operation is needed beyond the neonatal period. This approach involves a shorter hospital stay and fewer post-operative complications. © Cambridge University Press 2019.

The usage of recombinant activated factor VII (RFVIIA) during major and minor surgeries in severe hemophilia patients with inhibitor

WOS: 000356426905140